
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input type="button" value="点我" id="btn1">
<script>
    var btn1 = document.getElementById('btn1');


    //type,listener,useCapture
    //事件类型
    //监听的函数
    //捕获事件的方式
    var foo = function(e){
        console.log("foo1")
    }
    var foo2 = function(e){
        console.log("foo2")
    }
    btn1.addEventListener('click',foo);
    btn1.addEventListener('click',foo2);
    btn1.removeEventListener('click',foo)
</script>
</body>
</html>